The Travels of an Immortal
by Vinz48
Summary: Being immortal is not always beautiful, you often watch your loved ones die in front of you, while you continue to live, unable to reach them. And when are you the last living human on Earth? Well, you start jumping the dimensions! How will Harry behave in a world full of gods and monsters? Let's find out! HarryxHeraxHarem. Immortal!Harry Gray!Harry


**AN:** **Harry Potter and Percy Jackson and the Olympians do not belong to me, they belong** ** **, respectively,** to JK Rowling and Rick Riordan.**

 **Further AN at the end.**

 **Update:** **I just noticed that the chapter was full of errors that I thought I had already corrected, which I did now.**

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Chapter 1: A meeting with the troll

 _It happened in a theater, which the wings took fire. The Buffone went out to warn the public. They thought it was a joke and applauded; he repeated the warning: people exulted even more. So I imagine, that the world will perish between the general exultation of the witty, who will believe it is a joke. (Søren Kierkegaard)_

 _When one thinks of the end of the world, one thinks of the sun that dies, the earth that splits, even an alien invasion. However, when one thinks of the end of the world, one thinks it will be between millions, if not billions of years in the future, when humanity has already left our planet to reach more hospitable worlds._

 _No one had ever thought it would happen beforehand, no one had thought that because of man, the world would be over. Yet here it is, a world ravaged by war, with no living human being._

~ Break ~

 **Hogwarts Castle - At the top of the Astronomy Tower**

At the top of the tower of a castle now destroyed, sat a man of almost 20 years, black hair, a black T-shirt and black trousers, would have passed invisibly in the night without light, yet those emerald green eyes shone in the darkness.

Rocking his legs in the air, Harry Potter watched the bright stars in the night sky, ignoring the little grunts from the corpses below.

 _"A positive thing with this mess is that it's finally possible to look at the stars correctly."_ Harry Potter thought.

Lost in the admiration of the stars, Harry didn't notice the sudden presence of a man who had just appeared from nowhere.

"Ehhh, so you're the last survivor." Said a voice.

Without looking away from the sky, Harry replied, "Tell me, what a vampire does here, from what I know, all the vampires died out about 20 years ago."

"Eheh, who knows, maybe you didn't look well," said the unknown man.

"I doubt it," Harry replied.

"After all, there's no one besides me," Harry said with a sad smile.

"Well, now I'm here. By the way, I have not presented myself yet. My name is Kischur Zelretch Schweinorg, a magic expert, and a traveler of all dimensions, but you can call me Zelretch. "

Finally turning his head, Harry saw the newcomer. The figure in front of him was a huge, old man with gray, pointed hair and beard, wearing a black tunic that covered a black tuxedo. The British-looking gentleman's appearance was complemented by a golden stick that looked more like a problematic gauge than actually useful. But what caught Harry's attention was his eyes. They were deep crimson, like blood, characteristic of a vampire.

Seeing that it was his turn to presentations, Harry said "Hadrian James Potter-Black, magnificent wizard, last wizard on earth and apparently Immortal, but you can call me Harry."

"Come take a seat" Harry said, slapping his right hand at the side of his hand.

As the great wizard sat, with a snap of fingers, Harry materialized a crystal glass out of nowhere. Filling the glass with the wine from the bottle next to him.

Holding the glass to the newcomer, Zelretch took it, and taking it to his mouth took a sip.

"Mhmm, a Chatou Margaux of 1787, what a good year." Zelretch commented with a smile.

"An expert I see. Yes, it is a Chatou Margaux of 1787, I found a dozen of these bottles, in an old house abandons in France. A stroke of luck. "Harry said happily.

"But unfortunately this is already the last bottle." He said sadly.

"And you decided to share it with me? What an honor. "Zelretch said with a raised eyebrow.

"Well yes, after all, you're the first person I've been around for about 30 years, we have to celebrate." Harry commented.

"So, to our happy meeting, and to a funnier future." Zelretch said holding up his glass.

Looking at the man strangely for a few seconds, Harry raised the glass "to a less boring future," he said, before taking a sip.

After a few seconds of tranquility, Harry decided to speak first.

"So Zelretch, how you got to this world, after all, I'm 100% sure you were not on this world until a few minutes ago." Harry asked curiously.

"Ah, apparently I can't hide anything from you, Master of Death." The man said with an amused smile.

Frowning at the vampire's response, Harry asked, "how do you know that?"

"Well, to answer your question, I must first explain how my magic works. In my world there are two types of magic, Magic and Magecraft.

Magecraft or Taumaturgia is the artificial re-enactment of a miracle. It is the ability to realize what is possible through science with supernatural means; although the process is considered a miracle, the end result is not.

Instead, Magic is the highest form of magic in my world. It represents the actualization of events that are impossible to reproduce in a certain epoch, both by humans and by the planet.

At the moment there are 5 types of Magic:

The first and fourth are unknown.

The Second Magic, allows the magician to travel in different parallel universes.

The third magic allows the magician to partially resuscitate the souls.

The Fifth Magic allows the magician to travel in time. "Zelretch explained.

"As you have surely guessed, I practice the Second Magic, which I also call Kaleidoscope, which allows me to travel between dimensions."

"Hmm, interesting, and why did you end up here?" Harry asked.

"Well you see, being an immortal vampire, after a few decades, you start to get bored, so every now and then, I jump in other dimensions, I change something, and I see how the story continues with my intervention. It's fun. "The vampire said with a laugh.

"You know, I was also studying dimensional magic, looking for a way to go somewhere else, in fact tomorrow I was planning to use it for the first time, and see where it takes me." Harry revealed.

"Maybe one day you can teach me this your Second Magic?" Harry asked curiously.

"Hmm, I never thought of teaching someone my magic. I don't even know if it's possible, but the magic of this world is very similar to True Magic, so it might be possible. " Zelretch meditated.

"However I should take you with me, take you into my world and start experimenting. It could take years, and I'm not _so_ bored to start experimenting, "Zelretch murmured as he rubbed his beard.

"Too bad, I would have liked to learn." Harry said disappointed.

"Hey, I didn't say I will not teach you, of course I could not do it now, but maybe in the future." The vampire said with a smile.

"Always if you can find me between dimensions." Harry said.

"Hm, right." The old man murmured.

"Let's do this, since you already intended to sail to another world, what do you say if I take you there, in a world that I already know? You enjoy yourself in a new world, and I know where you are, a win-win situation. What do you think? "Zelretch asked.

"And what do you gain from this?" Asked Harry doubtfully.

"Well, I'm bored, and when I'm bored, I begin to create chaos in some dimensions.. So if I take you to a new dimension, you have something to do, and I have something to see. Satisfied with the answer? "

"Sure why not, after all I was ready to jump into a random size. Who knows, maybe I would have ended up in a size full of giant bugs. "Harry said disgustedly, with a shiver coming down the spine.

"Oh my God, I've already been to one of those worlds, and I assure you it's not a good thing." Zelretch said in disgust.

"Well, let's start?" Zelretch said standing up.

"Wait, you still have not answered my question, how do you know I'm the master of death?" He asked curiously.

"Ah yes, I could never forget this aura that surrounds you, after all, I know Death, she's an old friend of mine. Sometimes we meet together to look at some dimension. She knows so many dirty jokes. Too funny. "The old man said with a strange smile.

"Wait, is death a she?" Harry asked shocked.

"Of course it's her, what did you expect her to be, a boy? Stupid masculine children, "Zelretch said, annoyed.

"Wow, calm. I was only slightly shocked. You know, talking about the 'Death', I thought it was genderless. "Harry explained.

"Ah yes, a common mistake, but no, it's a girl."

"Anyway, how come I have his aura?" Harry asked confused.

"Mmmmh, let me think," Zelretch murmured, rubbing his beard.

"Ah yes, now I remember." Zelretch said snapping his fingers.

"Sometimes Death decides to make jokes like that, leaving some objects with a small part of her powers, all over the universe. Apparently you've got her ability to never die. "The old man said.

"As long as she doesn't die, which will never happen, you will never die." He explained.

"Ah man, that sucks. I have to spend eternity alone, "Harry said in a sad voice.

"Ah yes, I understand how you feel." Zelretch said, understanding the situation in which the boy was. After all, he too has spent centuries alone, with some love here and there.

"Wait up. Since you shared a good wine with me, maybe I have something to help you with. "He said as he began to search through his coat pockets.

While the old vampire was looking for something in his pockets, he decided to ask an important question.

"So where will you send me beautiful?" Harry asked excitedly.

"Hm? Ah yes, in a very interesting world. "The old man said with an amused expression.

"Come on let's go. Give me some more information. "Harry prayed.

"And where would the fun be? Don't worry, it will be a place full of adventures and interesting things. Who knows, maybe you'll find someone to love as well. "Zelretch said with a mysterious smile.

Meanwhile Zelretch had finished searching through his pockets, and had pulled out a bunch of ... cards?

"Let's see a bit." He murmured as he looked at the papers.

"Tamamo? Nahh. "

"Schathach? Naah, she wouldn't work well in that world. "

"Arturia? Nah, too serious. "

"Mordred? Nah, too problematic. "

"What the hell are you talking about, old man? Harry asked curiously.

Ignoring the boy's question, Zelretch kept looking.

"Medea? Nah, there's one already, "the old man murmured, before stopping at a card." Staring at the card, Zelretch looked at Harry, then at the card again, and then at Harry again.

"Yes, she will do very well for you." Zelretch said with a malicious smile.

"Old man, what the hell are you doing."

"Stay away from me! I do not trust your smile. "

"Wait, what do you want to do with that card ?! STAY AWAY! "Harry shouted trying to escape.

But with an absurd speed movement, certainly not normal for an old man, Zelretch found himself in front of him. He only had time to take a quick look at the card. It depicted a gold-haired girl with red eyes and wore a partial golden armor, only by the image he could see that she had a breathtaking beauty, more than any woman has ever seen.

He only had time to take a small look, before the old vampire inserted it into his chest, disappearing completely.

In panic, he quickly checked his chest, looking for something strange, but found nothing.

If he had more time and been more careful, he might have noticed that a small part of his magic moved to his chest and was absorbed into the card.

But unfortunately Harry didn't have to do a thorough check, because at that moment Zelretch opened a portal behind him.

As he was about to ask what he was doing, Zelretch pushed him through the portal.

"Damn you Zelretch! When I see you again, he swear I'll cut you to pieces! "Harry yelled before he fell into the portal.

"Be careful when you arrive, kid, there are many things on the other side that could hurt you. Sure, they would not be able to kill you, but they could create a lot of trouble. "

"Good luck, boy!"

He had only the time to listen to a final warning from Zelretch before falling into the portal for who knows where.

Seeing the boy disappear, Zelretch smiled, half-mad and half-amused.

"I can't wait to see what you will do with, Harry." He said before opening another portal and disappearing.

The castle that until recently, housed two great immortals, remained silent, only for a few grunts of animated corpses that were heard in the distance.

~ Break ~

Meanwhile Harry found himself floating in emptiness full of iridescent colors, moving and intertwining, looking like a kaleidoscope.

 _"Maybe that's why he called it that."_ Harry thought, remembering how Zelretch called his magic.

As he floated, Harry could see in his surroundings, strange bubbles with a succession of images inside, it was like watching a movie.

In one image he saw himself as he fought Voldemort. In another he saw an older version of himself with a red-haired woman, he recognized Ginny, along with five children in front of the red Hogwarts train at King's Cross station.

In another bubble he could see, a black-haired girl in the Hogwarts female uniform. She would have been any other girl, but those unmistakable green eyes, belied the idea, after all he saw them every time he looked in the mirror.

At that moment he realized that he was looking at a female version of himself.

 _"Of course, if there are more universes, why could not there be a female version of myself?"_ Harry thought.

 _"Of course, though, I'm really pretty as a girl."_ He thought as he watched the female version of himself fighting Voldemort.

However, there were not only other versions of himself, but in some bubbles, he could see worlds completely different from his own, with people never seen before.

In some, he saw a blond man in a white cloak with some red flames drawn at the end, while he was fighting a ... giant fox with nine tails?

 _"What the hell?"_ Harry thought.

In other bubbles close, he saw a smaller version of the blond man, but with 3 marks on each cheek, like a strange mustache, who fought against 6 men with orange hair and strange purple eyes with concentric centers instead of the pupil.

In another bubble, he could see some strange people with bats-like wings coming out of their backs as they fought against other people who had wings like pitch-black ravens.

In another scene he could see two people in armor fighting, one in crimson red, and the other in white and blue. They seemed to be fighting until they died, since the blows they gave, were all directed to vital points of the body.

As time passed, he saw several bubbles depicting different worlds. Some very similar to his, but others were completely different. He saw monsters, angels, demons, even fish with two legs. He saw fights, comic scenes, in some even sexual situations.

At one point he even swore he had seen a huge red dragon, with a big red horn on its snout, flying in the air, ignoring all the bubbles.

At one point, while he was looking in a bubble, his body was attracted in the other direction. He took speed, as he passed hundreds of bubbles, until he saw that he was attracted to a particular bubble.

He only had time to see an image with 12 giants seated on thrones arranged in a U shape, before being dragged into the bubble.

~ Break ~

 **Central Park**

Suddenly in a secluded area of Central Park. A portal opened, spitting out Harry Potter, who fell with his face on the grass.

"Damn, it's worse than Floo or dematerialization, and it pushes you through a very small pipe." Harry said sickly.

As soon as he recovered, he realized that he had lost control of his magic, making it leak out of his body.

Remembering Zeltrech's warning about not being detected, he quickly regained control of his magic, enclosing it again in his body, without letting anything escape.

He had to learn this trick, since the Muggles could find the magicians through the magic they expelled from the body.

However, he realized it was too late. He could feel a huge source of power heading toward him at high speed.

Deciding not to want to die as soon as he arrived on this world, he cast a quick concealment spell, along with one to erase the smell and the sound. Then he erased all traces of his presence in this place, and ran away.

~ Break ~

Not even five minutes later, a 16-year-old girl with auburn hair and silver eyes showed up where Harry had been before.

The girl looked around, looking for someone. Sniffing the air, looking for some smell, she was confused by the absence of something. Crouching on the ground, she saw that there were no traces to follow here either.

With a frustrated tongue pop, she stood up, slowly starting to shine. After a few seconds, when the light became blinding, she disappeared. Without leaving anything behind, not even the footprints, as if she had never come.

~ Break ~

 **Olympus - Hall of the Throne**

In a huge hall, in a floating mountain above the Empire State Building, 12 giants about 20 feet tall, were seated on large thrones arranged in a U shape with a large fireplace in the middle, looked after by a small 10-year-old girl with a beautiful dark red dress. The twelve thrones were very different from each other, there were those who were made entirely of gold or white marble, who was made similar to a robot and who looked like a fishing seat, complete with a ring to rest the rod , except that it was used for a trident.

The twelve giants were arguing among themselves.

"What's the situation?" Asked the bearded man with blue eyes sitting in the middle on a chair made of platinum, with drawings of lightening on the sides, also made of platinum.

"We do not know, brother" answered the man sitting on his left, dressed in a red Hawaiian shirt with green flowers, and a pair of Bermuda shorts, like a fisherman.

"Probably it must have been some dying monster, or a strange experiment by Hecate." The fisherman said.

"Could be. However we must never be too sure. We wait for Artemis to come back from her investigation and then decide what to do. "The god said at the center.

After a couple of minutes, the same little girl with amber-colored hair first appeared in the middle of the room.

Heading toward a throne made of silver, it had two date palms on her back, full moons above, with a wolf-skin cushion, she grew larger with each step she took. Until she was in the same height as the others, and sat on the throne.

"So Artemis, what did you find out?" The god in the middle asked.

"Nothing," replied Artemis sullenly with her arms crossed.

"You mean you've already eliminated the threat?" Asked the woman to the left of the god in the middle, sitting on an ivory throne with some depictions of a willow and a peacock.

"No, in the sense that there was nothing. No trace, no smell, no remnant of magic, nothing at all. "Artemis answered dryly.

"Surely an expert." Said a god seated on a throne made of leather and chrome with large human skulls embedded in his arms. He sat on a cushion made of human skin. "Or it was nothing special." Said a goddess sitting on a throne made of plants and ... cereals.

"Surely we can not ignore it, and if something dangerous is revealed?" Said a goddess seated on a silver throne, with a beautiful owl sitting on her shoulder.

"Whatever it was, we can get rid of it easily." Said the god seated on the throne made of leather.

"Arrogant as always, Ares." Answered a bearded and half battered god, seated on a mechanical throne made of bronze.

"Shut up Hephaestus, come back and play with your toys." Ares said.

"Silence." ordered the man in the middle.

With his order, the whole room became silent. Even those who were not interested in the discussion as the god wearing a leopard jumpsuit, seated on a throne made of vines, with a leopard-print pillow. And the goddess with a spectacular beauty, with an aura able to charm anyone, sitting on a throne made of silver and inlaid with aquemarine, beryls and other precious stones. The backrest has the shape of a large shell and the seat is made of soft swansdown. Both intent on reading a magazine.

"Now that I have your attention." The god said at the center.

"We will not do anything special, it was probably a monster that died." He explained.

"But Zeus, he had a power almost at the level of a minor god." Said a tall, muscular and tanned god like a Baywatch lifeguard, with long golden hair tied in a "man's sandwich" and eyes that shone like the sun. His splendor was exalted by the fact that he wore a golden Greek tunic.

"Silence, I don't care. I decided this way. The meeting is over. "Zeus ordered as he disappeared in a flash of lightning.

"Always so dramatic." The god said in a Hawaiian shirt as he disappeared into a puddle of salt water.

Soon all the other gods left, some by the door, and who disappeared in a flash of light.

Soon the room became dark and silent again, except for the little girl who took care of the fire with a firebrand.

"I have a strange feeling," said the little girl.

"I feel that things will soon become very interesting." She said with an amused smile.

~ Break ~

 **New York**

Harry didn't know he'd just avoided a bullet.

He was intent on relaxing in a beautiful bathtub of a 5-star hotel.

As soon as he got out of Central Park, he used his metomorfomagus skills to change his appearance. Goodbye were green eyes, and in their place a beautiful violet amethyst. The hair became blond, while the cheekbones of the face were realigned. At the end of the transformation it seemed like a perfect noble.

Looking around a little, he knew immediately that he had landed in New York. He looked very much like he remembered, but with no homes destroyed and zombies walking everywhere.

Deciding it was time to rest, he looked for the first hotel where to stay.

Fortunately for him, he found a beautiful 5-star hotel just a few meters from his location.

A simple and fast _Confundus_ to the receptionist, and had immediately an attic booked for a couple of weeks.

" ahhh, how beautiful is magic." Harry murmured as he lay down on the comfortable bed.

After a couple of minutes of silence, a loud snoring could be heard.

If he had been awake, he could easily have felt that the card housed in his chest had finally stopped absorbing magic, and had begun to pulsate and with every pulse, it began to shine more and more.

 **AN: Hello everyone. I am Vinz and after spending several months on this site, I decided to try to write my own story.  
I state that, this is my first ever story, and English is not my first language. For this reason there will be some grammatical errors, so be patient, and help me to improve.  
**  
 **This will be a crossover between Harry Potter and Percy Jackson and the Olympians, with a small addition from the Fate series.  
As you may have guessed, Harry's world is dead, as it happened, you will find out in the next chapters. I have to make a warning, this Harry has become immortal, completely immortal, like an Ajin, from the Ajind-Demi-Human series, and his personality will not be the same, after all he has lived for a long time, all his friends and his family died and he will never be able to rejoin them. We'll have a broken Harry, slightly darker, let's say neutral, he will not have problems killing a person, and he has no love for humanity, after all he's seen first hand what they can do.  
So we will not have any "saving people things", of course, if he finds someone in trouble, he will try to help her.**

 **I decided to try to write this story because there are not many ff between HP and PJ, in which Harry is not a demigod. so I told myself, 'cause not to write a story of an immortal Harry, and since I'm reading ff on Fate, I decided to add her too, I think you've recognized her now, even if she's a girl. By the way, I would like to ask your help to find a female name for her, since her name is too masculine for her.**

 **This will be a Harem, I have already decided that there will be 5 girls, including you, Hera, Hestia and two other girls to choose from, so you advise some girl to mate with, yet they must be immortal, so no demigod.**

 **Since it's my first story, I accept any kind of advice, suggestion and criticism to help me improve.**

 **The image is not mine, it belongs to Enuma00.**

 **That said, for today it's all, see you at the next update!**


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